Impact resistant shingle

ABSTRACT

An impact resistant shingle is provided, wherein the base mat is impregnated with an asphaltic material, with an asphaltic material on the upper surface of the shingle, and wherein another asphaltic material is disposed on the rear surface of the shingle, which other asphaltic material is softer with greater elongation than the asphaltic material used elsewhere in the shingle, such that crack resistance is afforded because energy from impact on the shingle is dissipated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of U.S. application Ser. No. 10/871,911,filed Jun. 18, 2004, which in turn is a continuation of Ser. No.10/288,747, filed Nov. 6, 2002, the complete disclosures both of whichis herein incorporated by reference.

BACKGROUND OF THE INVENTION

It is known in the shingle art that today's shingles are generally madeof a base mat of fibrous construction, most usually of fiberglassconstruction, that is impregnated with an asphaltic material. Theasphaltic material, generally bitumen, of some formulation is disposedon the upper surface of the base mat, and serves to adhere a layer ofmineral granules into the asphaltic material on the upper surface of thebase mat. Generally such occurs over the entirety of the upper surfaceof the shingle, but, such mineral granules can, if desired, be appliedonly to a visible portion of the upper surface of the shingle, to bevisible in the installed condition, and to be subject to elements ofweather in the installed condition.

Generally, the rear or lower surface of the shingle also has a layer ofasphaltic material, and usually has a fine layer of mineral granules,such as sand, talc, mica, or other mineral granules disposed on thelower surface of the shingle.

It has been found that when shingles that have been installed on a roofare subjected to various kinds of impacts, such as falling treebranches, workman walking on the shingles, or hail stones striking theshingles, especially during cold weather conditions, cracks can developin the lower surface of the shingle as a result of such impacts.

SUMMARY OF THE INVENTION

The present invention is directed to an impact resistant shingle, inwhich an asphaltic material impregnates the base mat of the shingle andthe upper surface of the shingle, but wherein an additional layer of amodified asphaltic material, having greater ability to resist crackingthan that of the principal asphaltic material and being softer than theprincipal asphaltic material, is provided, such that the softerasphaltic material is on the rear surface of the shingle that faces theroof on which the shingle is to be applied. When impacts from hailstones, tree branches, walking, or any other impacts are applied againstan upper surface of a shingle that is installed on the roof, the softerasphaltic material on the rear surface of the shingle provides a meansfor dissipating at least some of the impact, whereby crack formation onthe lower surface of the shingle is avoided. The modified asphalticmaterial should have the ability to dissipate mechanical energy. Apolymer modified asphalt can have such ability, such that it can resistcracking because it yields or flexes when sharply struck, rather thanfracturing.

Accordingly, it is a primary object of this invention to provide ashingle having a softer, impact-resistant layer of modified asphalticmaterial on its lower surface, that has a greater ability to resistcracking and a greater ability to dissipate energy under conditions inwhich the upper surface of the shingle is subjected to impact, than theother asphaltic material that is used in the manufacture of the shingle.

It is another object of this invention to accomplish the above object,wherein a layer of reinforcing material is applied to the rear surfaceof the shingle.

Other objects and advantages of the present invention will be readilyapparent to those skilled in the art from the reading of the followingbrief descriptions of the drawing figures, the detailed descriptions ofthe preferred embodiments, and the appended claims.

Thus, the present invention is directed toward providing a modifiedasphaltic material on the lower surface of the shingle, below the basemat, and preferably just above or below the layer of sand, talc, mica orother fine mineral application to the shingle or an application of afabric, paper, film, scrim or the like, such that the asphaltic materialapplied to the lower surface of the shingle, being softer, has anability to resist cracking and an ability to dissipate energy to agreater extent than the asphaltic material that generally comprises mostor all of the asphaltic material used in the rest of the shingle.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a front view of a shingle, showing multiple tabs separated byspaced apart slots, with mineral granules disposed on the upper surfaceof the shingle.

FIG. 2 is a horizontal sectional view, taken through the shingle of FIG.1, generally along the line of II-II of FIG. 1.

FIG. 2A is an illustration similar to that of FIG. 2, but wherein arelease liner is shown on the rear surface, instead of fine granules.

FIG. 3 is a horizontal sectional view, similar to that of FIG. 2, buttaken through a shingle having a layer of modified asphaltic materialspaced from the base mat by a layer of harder asphaltic material, butotherwise being similar to the illustration of FIG. 2.

FIG. 3A is an illustration similar to that of FIG. 3, but wherein arelease liner is shown on the rear surface, instead of fine granules.

FIG. 4 is a rear plan view of the shingle of each of FIGS. 1, 2 and 3,taken along the lines IV-IV of FIGS. 2, 2A, 3 and 3A (in the case ofFIGS. 2A and 3A, after removal of the release liner), wherein a windand/or crack-resistant layer of reinforcing material is applied to thelower, or rear surface of the shingle, and adhered thereto.

FIG. 5 is a representation of a fragmentary rear view of a shingle ofprior art type, in which the asphaltic material on the rear surface ofthe shingle displays a crack formation of a type resultant from impacton the opposite, or upper, front surface of the shingle.

FIG. 5A is a representation of a fragmentary illustration of the rear orlower surface of a shingle similar to that of FIG. 5, but wherein theshingle of FIG. 5A has a modified asphaltic material on its rearsurface, such that, after impact, no crack formation is illustrated.

FIG. 6 is a photographic representation of a rear view of a shingle ofprior art type, in which the asphaltic material on the rear surface ofthe shingle displays a crack formation of a type resultant from impacton the opposite, or upper, front surface of the shingle.

FIG. 6A is a photographic representation of the rear or lower surface ofa shingle, similar to that of FIG. 6, but wherein the shingle of FIG. 6Ahas a modified asphaltic material on its rear surface, and areinforcement layer, for example a scrim layer, such that, after impact,no crack formation is illustrated.

FIG. 7 is a vertical sectional view, taken through an alternativeembodiment of a shingle of this invention, wherein a two-layer laminatedshingle is illustrated, with each layer of shingle material beingconstructed like the illustration of FIG. 2.

FIG. 8 is a schematic illustration of the manner in which the layer ofmodified asphaltic material is applied to an otherwise-formed shingle,during the manufacturing process, by moving the shingle across anasphalt-applying roller.

FIG. 9 is schematic illustration of another method of applying a layerof modified asphaltic material to an otherwise formed shingle, whereinthe softer layer is applied as an already-formed layer of material.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

Referring now to the drawings in detail, reference is first made to FIG.1, wherein a shingle is shown, generally designated by the numeral 10.The shingle 10 is comprised of an upper headlap portion 11 and lower tabportions 12, with the tab portions being four in number. The various tabportions 12 are spaced apart by slotted openings 13.

The upper headlap portion 11 is that which is disposed above the upperends of the slotted openings 14. Left and right edges 15 and 16,respectively, of the shingle 10 have partial cut-outs 15 a and 16 a,respectively, such that when shingles 10 are aligned left-to-right,portions of slotted openings 15 a and 16 a will come together formingfull slotted openings.

With reference to the shingle of FIGS. 2 and 2A, the shingle 10 hasrespective upper and lower surfaces 7, 8 and is comprised of a base mat17 of preferably fiberglass mat construction, although the same can becomprised of organic mat, or fibered polymeric mat construction (or aconstruction comprised of combinations thereof), if desired. The mat 17is impregnated with a first asphaltic material 18, typically having asoftening point between about 100° F. and 160° F. when used with anorganic mat and between about 190° F. and 240° F. when used with afiberglass mat. The asphaltic material 18 preferably has a hardness asmeasured by penetration at 77° F. greater than about 30 dmm when usedwith an organic mat and a hardness greater than about 18 dmm when usedwith a glass mat. Disposed above the impregnated mat 17, 18 is a layerof asphaltic material 20 which, may or may not be of the same asphalticmaterial construction as the asphaltic material 18. If desired, theasphaltic materials 18, 20, may be comprised of a single layer.

Irrespective of whether the asphaltic materials 18 and 20 are comprisedof a single layer, or of multiple layers, there will normally bedisposed on the upper surface of the shingle, a layer of mineralgranules 21, which can, if desired, serve to deflect heat, infraredradiation, and ultraviolet rays, and which can provide a desired coloror pigmentation to the shingle 10.

Below the asphaltic impregnated mat 17, 18, there is provided anadditional layer of asphaltic material that is a modified asphalticmaterial, designated by the numeral 22. The asphaltic material layer 22is asphaltic material that is modified relative to the asphalticmaterials 18, 20, to be softer, having greater ability than theasphaltic material 18, 20 to dissipate energy and resist cracking at thetemperatures normally encountered on a roof, regardless of the ambientweather conditions, and regardless of the climate in which the roof isdisposed. The softness of the softer or modified asphaltic material 22can also be referred to as having a lower elastic modulus than that ofthe asphaltic materials 18, 20.

The layer 22 of modified asphaltic material can be provided directly tothe asphalt impregnated mat 18, or to another intermediate coating ofasphaltic material that has been applied to the impregnated mat 18, vialick-on, roll-on, fused powder-coating or spray-on techniques, orotherwise, as may be desired. More than one impact resistant layer or anumber of dissipative layers 22 may be used.

Preferably, the layer 22 of modified asphaltic material underlies theentire lower area of the shingle 10, or at least underlies the entireexposed portion of the shingle.

The modified asphaltic material of layer 22 should not be so soft as tocreate problems of sticking to an adjacent shingle when shingles arestacked together under warm conditions; however, such a concern, shouldit arise, could be alleviated by a layer 23 of fine granules, such assand, talc, mica or the like, or alternatively, a release paper, orliner 23 a, other parting agent or layer of fabric, paper, plastic filmor the like optionally applied beneath the layer 22, for assuringseparation between adjacent stacked shingles. The layer 23 or 23 a couldbe permanently or temporarily adhered thereto. The layer 22 of modifiedasphaltic material can optionally have self-adhesive properties forallowing the product to be adhered to a roofing substrate. In such anembodiment, the layer 22 will preferably be provided with a releasepaper or tape 23 a, or other parting agent, to allow stacking of theshingles prior to adhering them to a roofing substrate, after removal ofthe release agent to expose the self-adhesive layer 22.

The modified asphaltic material of layer 22 will preferably have afinite yield point and viscosity that is sufficiently high that thematerial 22 does not flow when in a packaged state, nor when shingles 10are installed on a steep-sloped roof in hot, sunny weather when they canbe subjected to internal or surface temperatures in the range of 140° F.to 180° F.

In the present invention, the modified asphaltic material 22 preferablyhas greater elongation or extensibility than the material 18. Theimproved elongation is preferably exhibited even at low temperatures,such as, for example, 30° F. The improved elongation can be a result ofthe presence of additives which also enhance the ductility at lowtemperatures and contribute greater resistance to changes in propertiesas a function of time or temperature than the asphaltic material 18.Preferably, the elongation of the modified asphaltic material 22 is atleast two percent, even after extensive exterior exposure, such as thatsimulated by accelerated ageing carried out by storing shingles madewith the modified asphaltic material at 158° F. for at least 10 weeks.

Preferably, however, the modified asphaltic material is not so soft thatits penetration at 77° F. is greater than about 150 dmm, as measuredaccording to ASTM D-5. Further, it is preferred that the lower surfaceof the modified asphaltic material be non-adhesive at ambienttemperatures, reducing the likelihood that the improved shingles willbecome stuck together during shipment and prior to installation, or thatthe modified asphaltic material will become dislodged by handling duringinstallation or subsequently thereto. Optionally, when a roofing producthaving self-adhesive properties in the modified asphalt material isdesired, a removable or peelable release liner in film or sheet form maybe applied to the lower surface of the shingle, so as to preventsticking together of the shingles during shipment or prior toinstallation, and subsequently removed when applying the roofing productto a roof substrate.

It is preferred that enhanced temperature elongation be achieved byincluding in the modified asphaltic material a composition comprisingone or more additives selected from elastomers, plasticizers, andresins, and blends thereof. Preferably, the elastomer is selected fromnatural rubber and thermoplastic elastomers, includingstyrene-isoprene-styrene block copolymer, styrene-butadiene-styreneblock copolymer, and styrene-ethylene-butadiene-styrene block copolymer.The formulation can also include one or more antioxidants, andadditional components such as oils.

The modified asphaltic material has greater elongation at lowtemperatures, such as about 32° F., than the asphaltic material 18 andretains an elongation at 32° F. of at least two percent even after yearsof exterior exposure, such that the shingle 10 shows no cracking underimpact.

The modified asphaltic material 22 may also have a lower modulus,especially at low temperatures, than the asphaltic material 18. That is,the modified asphaltic material is more extensible, as measured forexample by the absence of cracking under stress or impact conditions inwhich the material 18 would crack. In particular, the modified asphalticmaterial 22 preferably has an elongation at break at low temperature,such as at 30° F., of at least two percent, even after acceleratedageing simulating years of exterior exposure, such as at least ten weeksof storage at 158° F. The modified asphaltic material will also beinitially softer or have a lower initial modulus than the material 18,as measured for example by a higher penetration, particularly at highertemperatures. However, in non-self-adhesive applications, the modifiedasphaltic material 22 is preferably not so soft so as to be tacky oradhesive under ambient conditions, and preferably is not so soft as to“scuff” or suffer mechanical damage from handling during installation.

Under actual exterior exposure or simulated exterior exposure byaccelerated ageing, it is often found that the modulus of asphalticmaterials tends to increase such that the material becomes harder. Theincrease in modulus is often accompanied by a decrease in extensibilityor elongation. As “toughness” conventionally refers to the area under astress-strain curve, a material which requires increasing stress toattain a fixed strain as it ages can be said to be “tougher”. In thepresent invention, the modified asphaltic material 22 can become tougheras it ages, provided it retains the extensibility to provide anelongation at break of at least two percent.

Preferably, the enhanced extensibility is obtained by mixing anadditive, a preblended admixture, or several additives with the sametype of asphaltic material used for the asphaltic coating 18, and usingthis as the modified asphaltic material 22. For example, the material 18can be a standard coating-grade asphalt (softening point 200° F.-240°F.), and the modified asphaltic material 22 can be prepared by mixing ajelly-like premixed asphalt modifier, such as those blends comprisingfrom about 30 percent to 70 percent by weight of a thermoplastic blockcopolymer, the remainder comprising plasticizers, oils, antioxidants andthe like to promote polymer/asphalt compatibility and low temperatureflexibility. Examples of such asphalt modifying compositions include butare not limited to those sold by the Chemseco Division of SikaCorporation (Kansas City, Mo.) under the Sikamod™ trademark. Themodifying compositions are preferably blended with the steep or coatinggrade asphalt at a temperature between about 300° F. and 400° F., withagitation sufficient to produce a homogeneous mixture. The choice ofasphalt could also include an oxidized straight run type of asphalt thatcould be modified with a thermoplastic polymer.

Examples of polymeric materials which can be used include that which areknown to improve the physical, low temperature, and durabilityperformance characteristics of asphalt, such as atactic polypropylene(APP), isotactic polypropylene (IPP), styrene-butadiene rubber (SBS),chloroprene rubber (CR), natural and reclaimed rubbers, butadiene rubber(BR), acrylonitrile-butadiene rubber (NBR), isoprene rubber (IR),styrene-polyisoprene (SI), butyl rubber, ethylene propylene rubber(EPR), ethylene propylene diene monomer rubber (EPDM), polyisobutylene(PIB), chlorinated polyethylene (CPE), styrene ethylene-butylene-styrene(SEBS), and vinylacetate/polyethylene (EVA). Preferably a thermoplasticelastomer, such as a block copolymer of polystyrene, polybutadiene, andpolystyrene blocks is employed.

Plasticizers may be selected from the group consisting ofpetroleum-derived oils, phthalate esters (or their derivatives) andmellitates. Various petroleum resins, polyolefins, rosin (or itsderivatives,) tall oil, terpene and coumarone-indene resins can also beemployed.

With reference now to FIG. 3, it will be seen that a base mat 37 isprovided, impregnated with a first asphaltic material 38, having a layerof asphaltic material 40 thereon, which, like the embodiment of FIG. 2,may or may not be the same asphaltic material as that 38, and with alayer of granules 41 applied thereto, similar to that of the embodimentof FIG. 2. Another layer 42 of asphaltic material is applied beneath theimpregnated mat 37, 38, which layer 42 may or may not be comprised ofthe same asphaltic material that comprises that 38 and 40. In theembodiment of FIG. 3, the lower layer of asphaltic material 44 is thelayer of modified asphaltic material formulated as described above forlayer 22, and having the same characteristics thereof, and which has agreater ability to resist cracking and a greater ability to dissipateenergy that that of layers 38, 40. A layer 43 of fine granules, such assand, talc, mica or the like, or alternatively, a release paper, otherparting agent or layer of fabric, paper, plastic film or the like, isapplied beneath the layer 44.

Thus, in the embodiment of FIG. 3, the shingle 110 has respective upperand lower surfaces 27 and 28, similar to the respective upper and lowersurfaces 7 and 8 for the shingle of the embodiment of FIG. 2.

With reference to FIGS. 2A and 3A, it will be seen that the structuresare the same as with FIGS. 2 and 3, respectively, except that the rearsurfaces 8 and 28 are provided with a removable release liner 23 a, 43a, respectively, in lieu of a fine layer of granules, and that thelayers 22, 44, are self-adhesive, such that after the release liners 23a, 43 a are removed, the shingles 10, 110, can be adhered to asubstrate.

Referring now to FIG. 4, it will be seen that the rear surface of theshingle of either of FIGS. 2 and 3 appears the same, such that theillustration of FIG. 4 will be addressed only with respect to itsrelationship to the illustration of FIG. 3, it being understood that forpurposes of the illustration of FIG. 4, the same description can beapplied to a shingle as illustrated in FIG. 2.

The shingle 110, on its lower surface, is provided with a wind and/orcrack-resistant reinforcement layer 50. The layer 50 may comprise ascrim, or thin fabric, or it may be comprised of a plastic film, paper,parchment or foil. In the case of a scrim, the scrim could be knitted,woven, non-woven, laminated scrim or the like. In the embodiment shownin FIG. 4, the reinforcement layer 50 is shown as comprising a wovenconstruction, involving woven strands disposed at right angles to eachother, with a preferred density of, for example, nine strands in thevertical direction and nine strands in the horizontal direction persquare inch of reinforcement, covering the lower half of the rearsurface of the shingle behind the tabs, although the layer 50 could,cover less of the rear surface of the shingle or the entire rear surfaceof the shingle, if desired. The layer 50 could be a woven or non-wovenpolyester, which would tend to make it a thinner layer. The layer 50 ispreferably not applied deeply into the asphaltic material on the lowersurface of the shingle 1 10, but rather is preferably slightly embeddedinto or placed on to the surface 28.

The reinforcement layer 50 of scrim or other material will ordinarilynot be coated on its lower surface with a bitumen or other asphalticmaterial, nor will it have granules applied thereto, such that anyfilaments of the reinforcing material 50, especially those extendingvertically as shown in FIG. 4, can resist bending and resist failure inthe form of the likelihood of forming horizontal cracks across the upperend of the tab portion of the shingle when the shingle is bent upwardlywithin its elastic limit under forces applied by winds. However, ifdesired a thin layer of adhesive could be applied beneath the scrim orother reinforcement layer, with small particles of granular material,for example sand or the like, applied thereto. Additionally, thereinforcement material 50 may also serve to dissipate energy fromimpacts on the opposite, or upper surface, thus resisting crackformation on the rear surface. The vertical and horizontal strands ofthe reinforcement layer 50 can be of different materials, as may bedesired, or may be disposed at other angles other than 90 degrees, suchas diagonal, with or without vertical or horizontal strands. Optionally,the strands of the reinforcement layer could have random orientation,as, for example, from a non-woven web. Also, optionally, portions of thestrands could be knitted.

The reinforcement material 50 may be comprised of various compositionsother than fiberglass, such as polyester, and/or nylon, and thereinforcement 50 may either be slightly embedded in the asphaltic layer44 on the rear of the shingle 110, or may be adhered to the rear of theshingle by an additional post-applied thin layer of asphaltic ornon-asphaltic adhesive.

The asphaltic material that comprises the layers 22 and 44 may beconstructed in accordance with the second asphaltic binder disclosed inU.S. Pat. No. 5,347,785, or as is the second asphaltic binder ormodified asphalt as disclosed in U.S. Pat. No. 5,488,807, the completedisclosures of each of which are herein incorporated by reference, solong as they are in accordance with the above-mentioned characteristics.

Alternatively, the asphaltic material 22, 44, may be constructed of anyother formulation that meets energy dissipation and crack resistantconditions desired when the front surface of the shingle is subjected toimpact, so long as it is in accordance with the above-mentionedcharacteristics.

It will also be seen, with reference to FIG. 4, that a plurality ofadhesive zones 49 can appear on the rear surface 28 of the shingle,toward the lower end of the tab zone of the shingle, beneath the layerof reinforcement material 50, such that the sealant that comprises thesealant patches 49 may bond to a next-subjacent shingle on a roof, bypassing through openings in the mesh or web of the reinforcementmaterial 50. The patches of sealant 49 are therefore an option for theembodiment of FIG. 4. Such patches 49, may, if desired, be arranged in aband, as shown, and may also, optionally be as set forth in U.S. Pat.No. 5,239,802, the complete disclosure of which is herein incorporatedby reference.

With reference now to FIG. 5, it will be seen that a fragmentaryillustration of a multi-tab shingle 210 is illustrated as comprising ashingle portion of the prior art type. The illustration of FIG. 5demonstrates the result that can occur when impact against the uppersurface of the shingle 210 occurs, such as being struck by a rock, treelimb, hail stone or the like, and wherein the rear or lower surface 211of the shingle is subjected to cracking, in the form of what oftenoccurs as partially circular cracks 212 along with partially radialcracks 213, which can result in shingle failure.

With reference to FIG. 5A, a fragmentary illustration of a shingle 310in accordance with the present invention, wherein a modified asphalticmaterial 312 like that 22 of FIG. 2, having improved energy dissipationand crack resistance, is shown on the lower or rear surface of theshingle, and wherein the shingle of FIG. 5A has likewise been subjectedto impact on its opposite surface, but wherein no crack formation isvisible on the lower or rear surface 312 of the shingle of FIG. 5A.

With reference now to FIG. 6, the photographic illustration of a crack,similar to that of FIG. 5, is shown, where an impact has caused thecrack 315 on the rear surface of the shingle.

In FIG. 6A, a photographic illustration appears, wherein a reinforcementlayer, such as a scrim, is shown in the form of a rectangular grid onthe rear surface, overlying the surface of modified asphalt layer, andwherein a circular zone 320 appears in the shingle, showing evidence ofenergy absorption after impact, but wherein no crack appears. Theresidual pattern after the impact shows movement, but not fracturewithin the modified asphalt layer of the shingle.

With reference to FIG. 7, there is illustrated a vertical sectionalview, taken through a two layer laminated shingle, generally designatedby the numeral 410. The shingle 410 is comprised of a full heightshingle layer 411, constructed in section like the shingle of FIG. 2,which is adhered to a fractional layer, in this case, a substantiallyhalf-height shingle layer 412, with the layer 412 being substantiallydisposed against the posterior layer 413 of the shingle layer 411, belowthe headlap zone 414 thereof, to be disposed behind the tab zone 415 ofthe shingle layer 411. The half-height shingle layer 412 is likewiseconstructed like the shingle of FIG. 2, and the two shingle layers 411and 412 are adhered together where their surfaces mate, by a suitableadhesive, at 416, disposed in layer form. One or more portions of thehalf-height shingle layer 412 may optionally extend below the lower edge417 of the tab zone 415 of the shingle layer 411. Optionally, theshingle layer 412 could be a full back layer as shown in phantom in FIG.7, such that the entire shingle layer 412 is impact resistant.

Referring now to FIG. 8, it will be seen that a shingle layer 510,having granules 511 on its upper surface, already impregnated with anasphaltic material, is delivered along a horizontal path, in thedirection of the arrow 512, over suitable conveyor rollers 513 or thelike, to pass over an applicator such as that 514 of the roller-in-tanktype 515, wherein the modified asphaltic material 516, like that of 22in FIG. 2, disposed in the tank 515 is applied to the under surface 517of the shingle material 510, as it passes over the roller 514, rotatingin the direction of the arrow 518. In this manner, a thin layer ofmolten asphaltic material of the modified type can be applied, generallyat a factory installation, in liquid applicator form. Alternatively, anapplicator capable of a spray coating or other coating applicationmethod (not shown) could be used to apply the modified asphalticmaterial 516 to the under surface 517 of the shingle material 510.Following the application of the modified asphaltic material 516, thebottom side of the applied modified asphaltic layer like that of 22 ofFIG. 2 could be covered by sand, talc, mica or other fine mineralmaterial, or by a layer fabric, polymeric film, scrim, paper or the likeas 23 of FIG. 2.

With reference to FIG. 9, it will be seen that a layer of shingle 610having granules 611 on an upper surface thereof, is already fullyformed, except that a layer of modified asphaltic material 612, likethat 22 of FIG. 2, may be post-manufacture adhered, applied as analready-formed layer, by moving the same in the direction of the arrows613, and applying heat, or adhesive means, to adhere the layer 612 ofmodified asphaltic material, to the lower surface 614 of the shingle610. Thus, in the embodiment of FIG. 9, the layer 612 of modifiedasphaltic material may be provided either at the site of manufacture, orat the site of installation, as may be desired.

In either of the embodiments of FIGS. 8 and 9, the layer of material 516or 612 could alternatively be an impact energy dissipation layer havinga lower elastic modulus (i.e. being softer) and having the desiredelongation capability such as being comprised of a thin layer ofmembrane, self-adhesive or non-self-adhesive (in the latter case securedthereto by another adhesive), including but not limited to apolymer-modified asphaltic material layer or an elastomeric membranelike ethylene-propylene-diene monomer (EPDM). In the embodiment of FIG.9, the energy dissipation layer could be applied to the lower surface ofthe shingle or to a roofing membrane. Alternatively, the energydissipation layer could be applied to a roof substrate and the lowersurface of a shingle could subsequently be applied thereto.

In accordance with this invention, it will also be seen that there isprovided a method of making an impact resistant roof covering system. Inaccordance with such a method, a shingle is provided having a firstasphaltic material that has an elasticity as determined by a first levelof softness and a first level of elongation at break. A layer of asecond asphaltic material that has a second softness that is softer thanthe softness of the first asphaltic material, and which has a secondelongation at break that is greater than the elongation at break of thefirst asphaltic material. The second asphaltic material is applied to aroof substrate, and thereafter the shingle is applied to the roofsubstrate. Alternatively, the second asphaltic material can be appliedto the lower surface of the shingle prior to applying the shingle to theroof substrate.

It will be apparent from the foregoing that various modifications may bemade in the details of construction, as well as in the use and operationof the present invention, all within the spirit and scope of theinvention, as claimed.

1. An impact resistant shingle having upper and lower surfaces,comprising; (a) a base mat having upper and lower surfaces andimpregnated with a first asphaltic material; (b) the first asphalticmaterial having an elasticity as determined by a first softness and afirst elongation at break; (c) a second asphaltic material being on theupper surface of the base mat; (d) a layer of mineral granules beingdisposed on and adhered to the second asphaltic material on the uppersurface of the base mat, and comprising at least a portion of the uppersurface of the shingle; (e) a third asphaltic material being disposedbeneath the lower surface of the base mat; (f) the third asphalticmaterial being of a second softness that is a softer material than thesoftness of the first asphaltic material, and of a second elongation atbreak that is greater than the elongation at break of the firstasphaltic material, whereby; (g) energy from impacts on the uppersurface of the shingle is at least partially dissipated at the lowersurface of the shingle by the softness and elongation of the thirdasphaltic material, such that crack formation on the lower surface ofthe shingle due to impacts on the upper surface of the shingle, isavoided.
 2. The shingle of claim 1, wherein the first and secondasphaltic materials are of the same formulation.
 3. The shingle of claim1, wherein the first and second asphaltic materials are of differentformulations.
 4. The shingle of claim 1, wherein the third asphalticmaterial is disposed against the lower surface of the base mat.
 5. Theshingle of claim 1, wherein first asphaltic material is disposed againstthe lower surface of the base mat, and the third asphaltic material isdisposed below and adhered to the first asphaltic material.
 6. Theshingle of any one of claims 4 and 5, wherein the third asphalticmaterial is a liquid-applied coating during the manufacture of theshingle.
 7. The shingle of any one of claims 4 and 5, wherein the thirdasphaltic material comprises a sheet of asphaltic material, applied tothe shingle in sheet form.
 8. The shingle of any one of claims 1, 4 and5, wherein the shingle comprises a first thickness layer between upperand lower surfaces thereof, wherein a wind-resistant layer of a secondthickness of substantially thinner dimension than that of said firstthickness layer, is provided on the lower surface of the first thicknesslayer, over at least a portion of the lower surface of the firstthickness layer, adhered thereto.
 9. The shingle of claim 8, wherein thesecond thickness layer is adhered to the first thickness layer by anasphaltic material.
 10. The shingle of claim 8, wherein the secondthickness layer is adhered to the first thickness layer by the thirdasphaltic material.
 11. The shingle of claim 8, wherein a granularmaterial is disposed between said first thickness layer and the secondthickness layer.
 12. The shingle of claim 11, wherein the secondthickness layer is adhered to the first thickness layer by an asphalticmaterial.
 13. The shingle of claim 11, wherein the second thicknesslayer is adhered to the first thickness layer by the third asphalticmaterial.
 14. The shingle of any one of claims 1, 4 and 5, wherein thethird asphaltic material comprises a polymer-modified asphalticmaterial.
 15. The shingle of claim 8, wherein the second thickness layercomprises a material selected from the group consisting of any one of:(a) thin fabric; (b) plastic film; (c) paper; (d) parchment; and (e)foil; (f) metal screen; (g) plastic netting; (h) glass fibers pressedinto the second asphaltic material; (i) plastic fibers pressed into thesecond asphaltic material; or (l) spin blown fibers pressed into thesecond asphaltic material; (k) scrim.
 16. The shingle of any one ofclaims 2 and 3, wherein the shingle comprises a first thickness layerbetween upper and lower surfaces thereof; wherein a wind-resistant layerof a second thickness of substantially thinner dimension than that ofsaid first thickness layer, is provided on the lower surface of thefirst thickness layer, over at least a portion of the lower surface ofthe first thickness layer, adhered thereto, with the shingle having abutt portion adapted to being substantially covered by another shinglewhen applied to a roof and a tab portion adapted to being exposed toweather when applied to a roof, wherein the second thickness layercomprises crossing strands of reinforcing material disposed behind thetab portion of the shingle and substantially completely covering thesurface behind said tab portion of the shingle.
 17. A shingle accordingto claim 1, wherein the third asphaltic material has an elongation atbreak of at least two percent.
 18. A shingle according to claim 17,wherein the third asphaltic material has an elongation at break of atleast two percent measured at about 30° F. after ageing the shingle forat least ten weeks at 158° F.
 19. A shingle according to claim 17,wherein the third asphaltic material has a penetration of less thanabout 150 decimillimeters at 77° F.
 20. A shingle according to claim 1,wherein the third asphaltic material is non-adhesive at ambienttemperature.
 21. A shingle according to claim 1, wherein the thirdasphaltic material includes a softening composition comprising elastomerand plasticizer.
 22. An impact resistant roofing element having upperand lower surfaces, comprising; (a) a base mat having upper and lowersurfaces and impregnated with a first asphaltic material; (b) the firstasphaltic material having an elasticity as determined by a firstsoftness and a first elongation at break; (c) a second asphalticmaterial being on the upper surface of the base mat; (d) a layer ofmineral granules being disposed on and adhered to the second asphalticmaterial on the upper surface of the base mat, and comprising at least aportion of the upper surface of the roofing element; (e) a thirdasphaltic material being disposed beneath the lower surface of the basemat; (f) the third asphaltic material being of a second softness that isa softer material than the softness of the first asphaltic material, andof a second elongation at break that is greater than the elongation atbreak of the first asphaltic material, whereby; (g) energy from impactson the upper surface of the roofing element is at least partiallydissipated at the lower surface of the roofing element by the softnessand elongation of the third asphaltic material, such that crackformation on the lower surface of the roofing element due to impacts onthe upper surface of the roofing element, is avoided.
 23. A shingleaccording to claim 1, wherein the third asphaltic material hasself-adhesive properties, the self adhesive properties allowing theproduct to be adhered to a roofing substrate.
 24. A shingle according toclaim 21, wherein a lower surface of the third asphaltic material isprotected by a release agent surfaced layer, the release agent surfacedlayer being removable from the lower surface of the third asphalticmaterial to expose the self-adhesive third asphaltic material at thelower surface of the shingle.
 25. A method of making an impact resistantroof covering system, comprising the steps of: (a) providing a shinglecomprising a first asphaltic material having an elasticity as determinedby a first softness and a first elongation at break; (b) providing alayer of a second asphaltic material of a second softness that is softerthan the softness of the first asphaltic material, and of a secondelongation at break that is greater than the elongation at break of thefirst asphaltic material; (c) applying the layer of the second asphalticmaterial to a roof substrate; and, (d) applying the shingle to the roofsubstrate.
 26. The method according to claim 23, wherein the layer ofthe second asphaltic material is applied to the roof substrate prior toapplying the shingle.
 27. The method according to claim 23, wherein thelayer of the second asphaltic material is applied to a lower surface ofthe shingle prior to applying the shingle to the roof substrate.